Peel the potatoes and slice them into 3cm (1inch) pieces. Add them to a large saucepan with salted water, bring to the boil and boil for 15 minutes or until the potato is completely soft.
Meanwhile, toast the pine nuts in a pan on a medium heat for 3-4 minutes or until they begin to brown. Give the pan a shake every so often to prevent them burning.
Use a large slotted spoon to remove the potato from the saucepan and transfer to a mixing bowl, reserving the water for later. Leave the potato for a few minutes to steam dry so most of the moisture escapes, then add 2 tbsp of the nutritional yeast, the sage, and pinches of salt and pepper. Use a potato masher to mash the ingredients together until it’s completely smooth.
Transfer the potato to a floured worktop or a large chopping board. Pour half of the flour onto the potato and use your hands to fold the potato into the flour. Add the remaining flour and gently knead the dough until no creases remain. Avoid overworking the dough, otherwise the gnocchi will be chewy. If the dough feels too sticky, add more flour as you go.
Mould the dough into a ball and slice it in half. Roll out one half into a long sausage about 3cm (1 inch) thick, then slice the dough at 2cm (2/3 inch) intervals to create the gnocchi. Pick up a piece of gnocchi, roll it between the palm of your hands – compressing the dough to remove any creases – then roll it down the back of a fork to create those signature gnocchi grooves. Repeat until all the gnocchi pieces have been used up, then apply the same method to the remaining half of dough.
Bring the saucepan of leftover water back to the boil (add extra boiling water if necessary so it’s at least 10cm or 4 inches deep), then carefully drop in the gnocchi and give them a stir to prevent them sticking to the bottom of the saucepan. As soon as the gnocchi floats to the top it’s ready, so use a large slotted spoon to remove and transfer to a plate.
Add a tbsp or so of vegan spread to a large pan on a medium heat. As soon as the spread has melted, add the gnocchi to the pan and fry for 4-5 minutes, stirring occasionally to prevent them sticking to the pan.
Meanwhile, create the pesto by peeling the garlic and adding it to a food processor along with the rocket, basil, 2 tbsp of the toasted pine nuts, the remaining 2 tbsp of nutritional yeast, extra virgin olive oil, juice from the lemon, and pinches of salt and pepper. Process until the nuts have mostly broken down.
Slice the cherry tomatoes in half and add them to the gnocchi, then fry for another 2 minutes, stirring occasionally. It’s important you don’t cook them too long in the pan, otherwise they’ll lose their tenderness.
Remove the pan from the heat and stir in the pesto, along with the mixed leaves. Serve with the remaining pine nuts. Yuuuum!